Previously, using the iPhone on T-Mobile required customers to unlock their existing phones (or purchase an unlocked phone from Apple). But because of T-Mobile's incompatible 3G standards, users were instead restricted to the slower, EDGE network. That didn't stop many customers--in 2011, the carrier said it had 1 million iPhones on its network, and it's only amplified its attempts to market to iPhone owners since then.
The T-Mobile iPhone arrives on April 12; customers can being pre-ordering starting Friday, April 5.
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